More and more appliances rely on electrical power stored in batteries. This triggers an increased demand to generate electric power independently of a central power supply, for example, provided by the household electric outlets. In particular, for outdoor activities without having access to electric outlets, there is a desire to charge batteries with a commonly or at least under most circumstances, available energy source. Kinetic energy is one example of such source of energy that is in many situations available and which might be usable for charging different kinds of batteries. This kinetic energy can, for example, be provided by different kinds of vehicles, as for example, cars. Although most cars have already a power outlet which can be used for charging batteries, these outlets are typically very limited with respect to the available charging power. Therefore, it would be desirable to use directly the kinetic energy of the vehicle to generate electrical power in order to overcome the limits imposed by unavailable electric outlets.